Classical receivers can be divided into two categories, non-linear and linear receivers. While non-linear receivers e.g. maximum likelihood (ML) receiver [1]} can achieve an optimal symbol detection reliability, it suffers a high computational complexity due to an exhaustive search operation to find the ML combinations of user symbols. This leads to a long detection processing time and thus a high latency. The second type is the linear M-MIMO receivers; 1) minimum mean square error (MMSE) and zero forcing (ZF) receivers [2]}; and 2) iterative parallel interference cancellation (PIC) receivers that use a combination of maximum ratio combining (MRC) and decision statistic combining (DSC) schemes [3]}. MMSE and ZF receivers both rely on a matrix inversion operation to cancel multiple user interference which leads to an exponential increase in computational complexity with the number of antennas. In contrast, PIC receivers avoid the use of a matrix inversion operation. Specifically, PIC receivers iteratively performs MRC to estimate multiple user symbols used to reconstruct interfering symbols. The interfering symbols are then subtracted from the received signal to recover the desired symbols, in a parallel manner. Consequently, PIC receivers have a linear computational complexity and thus a much lower latency. Note that all above linear receivers exhibit poor detection reliability when compared to an ML receiver.
